package org.dfg.corejava.jdk7.aio.chatserver;

/*
 * Copyright (c) 2011 Oracle and/or its affiliates. All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 * 
 * - Redistributions of source code must retain the above copyright notice, this
 * list of conditions and the following disclaimer.
 * 
 * - Redistributions in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer in the documentation
 * and/or other materials provided with the distribution.
 * 
 * - Neither the name of Oracle nor the names of its contributors may be used to
 * endorse or promote products derived from this software without specific prior
 * written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

/*
 * This source code is provided to illustrate the usage of a given feature or
 * technique and has been deliberately simplified. Additional steps required for
 * a production-quality application, such as security checks, input validation
 * and proper error handling, might not be present in this sample code.
 */

import java.nio.ByteBuffer;
import java.nio.channels.CompletionHandler;

/**
 * Handles a cycle of reading / writing on the {@code Client}.
 */
class ClientReader {
	private final DataReader callback;
	private final ChatServer chatServer;

	ClientReader(ChatServer chatServer, DataReader callback) {
		this.chatServer = chatServer;
		this.callback = callback;
	}

	public boolean acceptsMessages() {
		return callback.acceptsMessages();
	}

	/**
	 * Runs a cycle of doing a beforeRead action and then enqueing a new read on
	 * the client. Handles closed channels and errors while reading. If the
	 * client is still connected a new round of actions are called.
	 */
	public void run(final Client client) {
		/*
		 * 客户端第一次连接时，callback为NameReader：先发送Name：提示用户输入昵称，然后接收用户昵称，向所有客户端发送通知，
		 * 最后把callback实例替换为MessageReader
		 */
		callback.beforeRead(client);
		client.read(new CompletionHandler<Integer, ByteBuffer>() {
			@Override
			public void completed(Integer result, ByteBuffer buffer) {
				// if result is negative or zero the connection has been closed
				// or something gone wrong
				if (result < 1) {
					client.close();
					System.out.println("Closing connection to " + client);
					chatServer.removeClient(client);
				} else {
					//第一次连接：读到的是客户输入的昵称
					//以后的连接：用户输入内容
					callback.onData(client, buffer, result);
					// enqueue next round of actions
					client.run();
				}
			}

			@Override
			public void failed(Throwable exc, ByteBuffer buffer) {
				client.close();
				chatServer.removeClient(client);
			}
		});
	}
}
